Media delivery systems are used in a wide variety of applications. For example, they deliver individual sheets of paper from a stack of papers through printers, copiers, and the like. Usually, these delivery systems include elongate and serpentine media paths for the media to travel down. Various driven rollers and other media movers are usually placed along the media path to operably engage the media and urge the media along the path.
Each sheet of media within the media delivery system must be appropriately aligned, or squared, with respect to the related printing, copying, or scanning mechanism. However, individual sheets of media frequently become skewed either upon entering the media delivery system or while traveling through the media path.
In many cases, these media delivery systems are expected to deliver different sized media, such as letter paper, envelopes, address labels, and note cards, equally effectively through the delivery system. Moreover, these media delivery systems are also expected to handle media having different weights and grades.
These variabilities in media sizes, weights, and grades, further increase the likelihood of an individual sheet within the media delivery system becoming inadvertently skewed. For example, some printers and copiers allow printing on both sides of a sheet of paper, a function commonly known as duplexing. The media path for such operations usually includes reversing the direction of the paper through the media path after one side of it has been printed on, and guiding the paper through a second media path that turns the paper over and re-delivers the paper to the same printing mechanism so that the second side of the paper can now be printed upon. The apparatus forming this second media path is frequently called a duplexer. These media delivery systems usually include a plurality of driven rollers along the media path to urge the paper in the desired direction along the path. However, fewer rollers operably engage smaller sized paper in the duplexer. Accordingly, unlike larger sheets of paper in the media path, this smaller sized paper tends to pivot slightly about the fewer engaging rollers, thereby becoming skewed.
The present invention is a skew-correcting media delivery system and method for driving media along a media path. A driver urges the media in a first direction and an opposite second direction along the media path. A substantially flat surface, which is aligned substantially perpendicular to the second direction, extends into the media path such that the trailing edge of the media operably engages the substantially flat surface when the media is urged in the second direction thereby aligning the media in the media path.